1. Field of the Invention
The present invention relates to a printing system and printing device that are shared by a plurality of users, and so on.
2. Description of the Related Art
Recent years have seen the widespread use of image forming apparatuses that have various functions such as copying, scanning, faxing, and Internet Protocol (IP) communication. Such an image forming apparatus is called a “Multi-Functional Peripheral” (MFP) or a “multifunction device”. The various functions are applied by applications in different ways, which enables an image forming apparatus to provide users with a wide variety of services. Some services are proposed which are offered by the image forming apparatus working in conjunction with a server.
One of such proposed services is called “pull printing”. According to the pull printing service, print data sent by a terminal such as a personal computer is temporarily held on a server named “pull printing server” instead of being received promptly by an image forming apparatus. The pull printing server receives sets of print data from personal computers installed in different locations and manages the sets of print data collectively. When a user goes to the installation site of a certain image forming apparatus and performs predetermined operation thereon, the pull printing server sends print data of the user to the image forming apparatus.
According to the pull printing service, a print job is executed after the user gets to the installation site of the image forming apparatus. The service therefore enables the user to obtain a printed matter based on the print job more reliably than the case where the print job is executed immediately after the print data is sent directly to the image forming apparatus without a server.
Meanwhile, one user sometimes instructs an image forming apparatus to execute a plurality of jobs through the pull printing service. In such a case, it is desirable that printed matters produced based on the jobs are not confused with the other printed matters related to the other users.
To cope with this, the following method has been proposed. In a printer which is connected to a network to receive printing data and prints the data, an IP address of an apparatus which transmits data is managed together with printing data, and the sequence of received data is managed together with printing data, whereby data sent from the same apparatus is printed out consecutively (see the English Abstract of Japanese Laid-open Patent Publication No. 2004-058501).
A print server stores pint jobs accepted from a PC in a storage unit in order to wait for printing of a printer; however when it becomes possible to transmit the print jobs to the printer, the print server issues a print execution instruction to a print job at a top of print order and transfers the instruction to the printer, and if a print job of the same user as the print job to which the print is instructed is stored in the storage unit, the print server changes the print order so that the print job of the same user is issued a print instruction in succession the print job to which the print execution instruction has been issued (see the English Abstract of Japanese Laid-open Patent Publication No. 2008-090385).
In some cases, a plurality of users shares one terminal. In other cases, while a printing device receives a plurality of sets of print data in succession from one transmission source, the printing device receives print data from another transmission source.
In such a case, according to the conventional methods, the printing device sometimes executes, between a plurality of print jobs instructed by one user, a different print job related to another user. This probably causes confusion between printed matters related to one user and the different printed matter related to the other user.
The present invention has been achieved in light of such an issue, and an object thereof is to prevent desired printed matters produced based on print jobs instructed by a specific user from mixing with another printed matter produced based on a print job instructed by another user.